Bayer Expert Guide Meadow-Grass Management in Winter Cereals
Total Page：16
File Type：pdf, Size：1020Kb
Bayer Expert Guide Meadow-grass Management in Winter Cereals www.bayercropscience.co.uk Introduction Copyright of photographs The term ‘meadow-grasses’ refers broadly to a group of around fifteen Poa species found in the UK. A few species are widespread All photography © Bayer CropScience Ltd 2015, except where indicated. and common; others very rare with only three of significant importance to the farmer. These are annual meadow-grass (Poa annua), rough meadow-grass (Poa trivialis, also known Active substances and trademark acknowledgements as rough-stalked meadow-grass) and smooth meadow-grass (Poa pratensis, also known as smooth-stalked meadow-grass). Atlantis®, Bacara®, biopower®, DFF ®, Liberator®, Movon®, Othello® and Vigon® are registered trademarks of Bayer. Of the three, both annual meadow-grass and rough meadow-grass are commonly found as weeds in arable and horticultural crops Atlantis WG contains mesosulfuron-methyl and iodosulfuron-methyl-sodium. Bacara contains diflufenican and flurtamone. (1,9,38,41,43). Liberator contains flufenacet and diflufenican. Othello contains diflufenican, iodosulfuron-methyl-sodium and mesosulfuron-methyl. Movon and Vigon contain flufenacet, diflufenican and flurtamone. Although smooth meadow-grass is widespread The objective of this booklet is to aid and assist Use plant protection products safely. and frequently found as a constituent of pastures, in the identification of these more common Always read the label and product information before use. grassy banks, roadside verges and field margins, meadow-grasses, and give an insight into their Pay attention to the risk indications and follow the safety precautions on the label. it is not usually a serious or persistent problem distribution and biology, and guidance on their For further information, please visit www.bayercropscience.co.uk or call Bayer Assist weed in arable crops (1,41). It is most often seen control in winter cereals. on 0845 6092266 (calls cost 5p per minute plus your telephone company’s network as an arable weed following ploughed up access charge) or 01223 226644. permanent pastures or grass seed crops (36). © Bayer CropScience Limited 2015. 2 3 Contents 1 Distribution of meadow-grasses 6 2 Economic implications of meadow-grass infestations 8 3 Reasons for the presence of meadow-grasses 9 4 Growth habit, biology and characteristics of meadow-grasses 10 4.1 Annual meadow-grass 10 4.2 Rough meadow-grass 10 4.3 Smooth meadow-grass 11 4.4 Identification characteristics of meadow-grasses 11 5 Meadow-grass control 14 5.1 Preventing new infestations 14 5.2 Herbicide resistant weeds 14 5.3 Key herbicides available for the control of meadow-grasses 15 6 Use of Othello for meadow-grass control in winter cereals 17 7 References 18 Meadow-grass 4 5 1 Distribution of meadow-grasses Whilst annual, rough and smooth meadow-grass are widespread and More recently in 1998/99, another survey of 569 Source GfK Kynetec. arable field headlands in the UK found that annual found in every county in the British Isles (2,3), only annual and rough meadow-grass occurred on around 40% of those meadow-grass are commonly found in arable crops. covered – making it almost twice as common as rough meadow-grass and almost five times more common than smooth meadow-grass (34). In 1981, a survey of winter wheat and barley crops Rough meadow-grass was considerably less conducted throughout Central Southern England, common, with the highest frequency being A survey in 2011 of 1,350 arable farmers in Britain reported that meadow-grasses (predominantly recorded in some areas of mixed farming. showed that 34% of farms applied herbicides Figure 1 annual and rough meadow-grass) were present The least common was smooth meadow-grass, specifically to control meadow-grass species (45) in 35% of fields throughout the area (24). the highest frequency being found in South East (Figure 1). The darkest red indicates the areas of Subsequent studies have shown that both annual and North Wales – and on average in only around most intensive herbicide usage specifically for and rough meadow-grass can also be found in 20% of fields visited. Throughout the remainder meadow-grass control. The paler areas in the spring-sown cereals (9,36,37,43). of Britain the frequency was around 10-20% of south and east of England however, do not fields infested (30). necessarily indicate a low incidence of meadow- A survey in 1991/92 showed annual meadow- grass. It is more likely that herbicides used for other grass to be the most common of the three Table 1 gives an indication of the areas worst and problem grasses, such as black-grass, have also meadow-grasses, being both very frequent and least affected by these three species. controlled meadow-grasses as a secondary target widely distributed in arable fields throughout Britain. weed in these counties. Table 1: Relative frequency of annual, rough and smooth meadow-grass throughout Of the remaining twelve species of meadow-grass Britain (1991/92) found in Britain (Table 2), nine are either rare or very rare – confined mainly to mountainous or rocky areas; and three, whilst frequent, are only found in Species Areas recorded as most Areas recorded as less woodlands, shady areas or on thin, dry soils. All are common common Key: Incidence of spraying for meadow-grasses unlikely to be encountered in arable situations (1). Annual meadow-grass Kent, Surrey, Sussex, Bedfordshire, Essex, Hampshire, Isle of Wight, Cambridgeshire, North Common throughout Britain: Berkshire, Norfolk, Teesside, Lincolnshire and Humberside, found in around 40-100% Lowest Highest Durham, Lancashire, Cumbria, South Yorkshire, South Wales, of fields surveyed Figure 1: Intensity of herbicide use for Cornwall, West and North Argyll and Bute meadow-grass control in cereals 2011 Wales, Northumberland, Dumfries and Galloway Rough meadow-grass Powys, Isle of Man, Hampshire, East Anglia, Bedfordshire, Table 2: Other meadow-grasses (Poa spp.) found in Britain Isle of Wight, Berkshire, Kent, Oxfordshire, Somerset, Occurs throughout Britain Surrey, Sussex, Wiltshire, Avon, Lincolnshire, South Yorkshire, but only found in 10-60% East and West Midlands, Lancashire and Cumbria, North Early meadow-grass Poa infirma H.B.K. Glaucus meadow-grass Poa glauca Vahl. of fields surveyed Gloucestershire Wales, Central and North Bulbous meadow-grass Poa bulbosa L. Swamp meadow-grass Poa palustris L. Scotland Alpine meadow-grass Poa alpina L. Broad-leaved meadow-grass Poa chaxii Vill. Smooth meadow-grass Monmouthshire, Dorset, Hertfordshire, Nottinghamshire, Berkshire, North Wales and Bedfordshire Wavy meadow-grass Poa flexuosa Sm. Narrow-leaved meadow-grass Poa angustifolia L. Occurs across Britain, but only Anglesey, Northumberland and Wood meadow-grass Poa nemoralis L. Spreading meadow-grass Poa subcaerulea Sm. found in a maximum of 20% Durham, South West Scotland of fields surveyed Balfour’s meadow-grass Poa balfouri Parv. Flattened meadow-grass Poa compressa L. 6 7 2 Economic implications of meadow-grass 3 Reasons for the presence of meadow-grasses infestations Weed competition can impair cereal establishment Although not as competitive as some other annual In contrast to black-grass and brome grasses, the reasons for the and growth, resulting in reduced yields or poor grass-weeds, such as wild oats and bromes, grain quality. Where grass-weeds are present in the effects of meadow-grasses on crop yields presence of meadow-grasses are less clear-cut. cereals the incidence of Barley Yellow Dwarf Virus are not insignificant. Rough meadow-grass for (BYDV) and some fungal pathogens, such as ergot example, is more competitive, plant for plant, The increase in frequency of grass-weeds in cereals (Claviceps purpurea), may also be increased. than black-grass (9,36). may be partially attributed to the widespread use Lodging caused by weeds can also make of both hormone-based, and other broad-leaved Of the two ‘problem’ meadow-grasses, rough harvesting difficult, time consuming and reduce weed herbicides throughout the late 1950’s to mid meadow-grass is the more competitive. Table 3 grain quality (36). 1960’s. It has been suggested their use caused a compares the competitive effect of some annual decline in susceptible broad-leaved species, leaving If uncontrolled, particularly in thin crops and under grass-weeds on winter wheat yields. grass-weeds uncontrolled and with potentially less moist growing conditions, meadow-grasses can competition (4,5,6,11). rapidly take hold to form a dense mat at the base Whilst there is little evidence on the competitive of the crop. effects of smooth meadow-grass in cereals, it is Annual meadow-grass is found on most soil types anticipated that, where it exists, it is likely to be and in most situations – especially where land is Even moderate populations of annual meadow- comparable to that of rough meadow-grass, as disturbed. It is dispersed on the wind and by both grass can still give rise to a decrease in cereal it is of both similar size and growth habit. animal and human intervention. It is therefore yields of up to 6%, although with very dense unsurprising that it is a very common weed in infestations (greater than 1,000 plants/m2), losses both UK agriculture and horticulture. of up to 25% have been recorded under moist conditions (10). In contrast, rough meadow-grass is essentially a perennial pasture grass that has gradually moved into arable cropping as pastures have been 2 Plant No. of plants/m ploughed up, particularly in mixed farming areas. Wild oat (Avena spp.) 0.5 In other areas it has also moved in from grassy field margins and field tracks, being spread by seed and Brome grasses (Bromus spp.) 3 vegetative means (22). Rough meadow-grass (Poa trivialis) 5 Direct drilling and minimal cultivations also favour Black-grass (Alopecurus myosuroides) 8 the germination and emergence of meadow- grasses, as most of their seeds (being stimulated Table 3: Number of plants shown to give a 2% yield reduction in winter wheat by light) germinate on or close to the soil surface (7,35).